Worm-grinding machine



D. FITZPATRICK.

WORM GRINDING MACHINE. glflmcmon men AUG.2. I915.

1,340,030. Patented y 11, 1920.

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will? D. FITZPATRICK.

WORM GRINDING MACHINE.

APPLlCATtDN FILED AUG-2,1915.

1,340,030. Pat nted May 11, 1920.

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Patented May 11, 1920.

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D. FITZPATRICK. WORM GRINDING MACHINE.

APPLICATION FILED AUG|2| I915. 1,340,030, Patented May 11, 1920.

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D. FITZPATRICK.

WORM GRINDING MACHINE.

APPLICATION FILED AUG.2. 1915.

1,340,030. Patented y 11, 1920.

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D. FITZPATRICK. WORM GFHND'NG MACHINE.

APPLIATION FILED AUG-2.1915.

1,340,030, Patented May 11, 1920.

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D. FITZPATRICK.

WORM GRINDING MACHINE.

APPLICATION FILED AUG-2. 915.

1,340,030. Patented y 11,1920.

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WORM GRlNDING MACHINE.

APPLICATION FILED AUG-2. I915.

1,340,034) Patented May 11, 1920.

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D. FITZPATRICK.

WORM GHlNDING MACHINE.

APPLICATION FILED AUG.2. 1915.

1,340,030, Patented May 11, 1920.

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2222/52/02? 20m a lfifzam 1/ W PM.

Zzzs 42101775 5 UNITED STATES PATENT OFFICE.

DAVID rrrzra'rmcx, or CLEVELAND, OHIO, AssmNon To THE CLEVELAND WORK at GEAR COMPANY, or CLEVELAND, OHIO.

WORM-GRINDING MACHINE.

Specification of Letters Patent.

Patented May 11 1920.

Application filed August 2, 1915. Serial K0. 43,175.

To all whom it may concern:

Be it known that I, DAVID FITZPATRIOK, a citizen of the United States, and resident of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in lVorm-Grinding Machines, of which the following is a specification.

My invention relates to a machine for grinding worms or similar machine parts aving convolute threads.

At the present time worms are machined to size by means of hobbing tools. cases, however, it is necessary to temper the worm after it has been cut, and in the hardening process inaccuracies are almost certain to develop. The object of the present invention is to provide a machine which will automatically and accurately grind the worm to size after it has been tempered.

In a worm cutting machine the length of time re uired for the bobbing tool to make a comp ete cut through one thread is so great that the time element is not a matter of great importance. Therefore, at the end of a cutting travel of the hobbing tool the operator backs the tool away fromthe worm by hand, indexes the worm by hand, re verses the machine by hand, and runs the tool back to the other end of the worm, and then draws the tool into cutting position and starts it on its forward travel.

On the other hand, with a grinding machine, the grinding wheel may pass through the worm in a few seconds and the time con sumed in making the various changes by hand, as is done in the cuttin machine, would beat matter of considera le importance.

In other words, in a cutting machine, if it took an hour to make each cut. a matter of three or four minutes consumed in making the changes would be of minor importance, and the machine would be doing work the greater part of the time.

On the other hand, in a grinding machine, if it took fifteen seconds to make a cut. a matter of three minutes in making the changes would be of substantial importance, and the machine would be doingwork only a relatively small portion of the time. Therefore, in a grindlng machine it is essential that as many as possible of the operations be peformed automatically.

According to my invention all of the changes may be made automatically, but I In some ,1 prefer to utilize manual means for adjusting the depth of cut to be taken by the grinding tool from time to time as the worm 1s being ground.

In the preferred form of my invention the grinding wheel is moved lon ltudinall with respect to the worm, but I 0 not limit myself to this form of construction. In this preferred form the apparatus automatically performs a cycle of movements. The grinding wheel passes through one thread of the worm in grinding contact therewith. It is then withdrawn and the worm indexed by advancing it one thread. The whole machine is then reversed, and the grinding wheel travels back across the worm but out of contact therewith until it reaches the limit of its travel, when it is brought forward into grinding contact and the cycle of operations repeated. It is only necessary for the operator to occasionally advance the tool. slightly so as to take a deeper cut.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawin s and in part will be more fully set forth in the following particular description of one form of mechanism embodying the invention, and my invention also consists in oer tain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the accompanying drawings:

Figure 1 is a front elevation of a completed machine disclosing a preferred embodiment of my invention;

Fig. 1 is an enlarged detailed view of the upper portion of the reversin wheel shown at the front of the machine in iig. 1*;

Fig. 1 is a transverse sectional view taken on the line 11 of Fig. 1 looking in the direction indicated by the arrows;

Fig. 1 is an enlar ed sectional view taken on the line 1' 1 0 Fig. 1;

Fig. 1 is a view partially in front elevation and artially in section on the line 1 -1 of ig. 1;

Fig. 2 is an end elevation of the right side of the machine shown in Fi .1 with the pulley and its driving belt omitted;

Fig. 2 is a longitudinal sectional view taken axially through the emery wheel spindle and taken on the line 2 2 of Fig. 2;

Fig. 3 isoa view similar to Fig. 2* showing the opposite or left end of the machine;

ig. 3 is an enlarged sectional view taken 3 3 is a view similar to that shown with the stop plate in rotating is a view of the rear elevation of the machine;

Fig. 5 is a plan view of the machine; Fi 5 is a view similar to Fig. 5 with certain superstructures removed to expose the interior arts of the machine;

Fig. 5 is a horizontal sectional view taken on the lines 5-5 of Figs. 4 and 6;

Fi 6' is a longitudinal vertical sectiona view taken on the line 6"--6 of ig. 6 is a transverse vertical sectional view taken on the line 6"-6 of Figs. 6 and 5";

Fig. 6 is a plan view partly in section of the worm-work showing an adjacent por tion of the emery wheel in grinding position relative thereto;

Fig. 6 is a view similar to Fig. 6 showing the relative positions of the work and emery wheel when in the return traverse position;

Fig. 7 is a transverse vertical sectional view taken on the line 7 --7 of Fig. 5, ap roximately at the center of the machine;

ig. 7 is a vertical transverse sectional view taken on the line 7 -7 rOf ig 5 Fig. 7 is a view similar to Fig. 7 taken on the line 7--7 of the Fig. 5;

Fig. 7 is a fragmentary plan view of the tool head partly in section on the line T -T of Fig. 7

Fi B is a vertical longitudinal sections view at the back of the machine, taken on the line ES -8 of Fig. 5;

Fig. 8 is a vertical sectional view through parts of the tool head, taken on the line 8 8 of Fi 5;

Fig. 9 to 9 inclusive are details of the reversing trip shown in section in Fi 9; Figs. 9 and 9 being taken respectiveon the lines 99 and 9-9 of Fig. 9; Figs. 9 and 9 being shown in different operative positions;

Figs. 10 to 10 inclusive are enlarged views of portions of the indexing mechanism shown in plane in Fi 5; Fig. 10 showing the parts when tfie emery wheel is in its grinding position; Fig. 10 when the parts are in their work indexing position; and Fig. 10. when in their reverse traverse position; v

Fig. 11 is an enlarged vertical sectional view taken through the head stock of the same parts shown in Fig. 6 scale;

Fig. 11 is a horizontal sectional view taken on the line 11 --11 of Fig. 11";

Fig. 11 is a vertical sectional view taken on the line 11--11 of Fig. 11 and the similar line in Fig. 11

Fig. 11 is an end elevation of the work plate and dogl taken sectionall v through thii1 work on t e line 1111 of Fig. 11"; an

Figs. 12 and 12' are views respectively similar to the views shown in Figs. 1 and a? showing the emery wheel in position in its inoperative return.

In the following description and in the claims, the parts will be described briefly in order to condense the specification and will he identified b v specific names for convenience of expression. but they are intended to be as generic in their applicationto similar parts as the art will permit. Parts. the length of which extend parallel to the front of the machine. will be referred to as longitudinal members while parts extending from front to rear will be referred to as transverse members. The descri tion of parts which are obvious from the rawings have been either condensed or altogether omitted.

Figs. 3

on reduced 9 and 10 show the position of Fig. 8 is a orizontal sectional view taken the parts while the work is being indexed at on th li 8' 8 f Fig, B the end of the grinding traverse; F1 5. 65, Fig. 8 is an enlarged plan view of the 10, 12 and 12 show the parts will? the construction shown on the line 8 -8 of grinding wheel is on its inoperative traverse ig. 8 is a transverse sectional view taken on the lines 8"-8 of Fig. 8;

Fig. 8' is an enlarged view of the handle and a section of certain adjacent parts shown in ig. 8; q

Fi 8 is a transverse sectional view taken on t e line 8-8 of Fig. 8*; a

Fig. 9* is an enlarged view partly in horizontal section of certain of the driving mechanisms shown to the right of Fig. 5

Fig. 9 is a vertical transverse sectional view taken on the line 9"- 9 of Fig. 9 and on the similar line on Fig. 10;

and all the other figures show the parts of the machine when the grinding wheel is operatively engaging the worm on its grinding traverse.

F mine. head stock and tail stock.

drawings, there is In the accompanyi ii? machine including shown a lathe type .a hollow box like supporting bed frame 40 (Fi 1")v desi ned o inclose most of the mec anism an extending n wardly from the left end of which is a ollow box 41 constituting the head stock of the machine. A cover plate 42 is bolted to the top of the tsetse box to inclose the live center driving mechanism therein. work table 43, provided with longitudinally extendin guideways 44 (Fig. 5 is fixed to the ront portion of the top of the bed and extends from the head stock 41 to the right end of the frame 40. A longitudinally movable tail stock 45 is slidably mounted on the uideways 44 and is adj ustably fastened to t e work table by means of bolts 46 as is usual with similar lathe constructions. V

The tail stock carries a longitudinally adjustable slide 47 (Fig.12 controlled by an adjusting thumb-screw 48 for moving the dead center 49 to and from the live center 50 carried by the head stock. The work W is centered between the pointed ends of the live and dead centers. The dead center is locked in position bearing on'the adjacent end of the work by means of a clamping screw 51 carried b the tail stock and designed to bear on t e side of the slide 47-.

Tool carriage.

The upper portion of the bed 40 to the rear of the table 43 (Figs. 2 and 7*) and head stock 41 provides a support for a tool carriage bodily movable longitudinally of the machine. his carriage includes a bottom member 52 constituting a bed plate. This bed plate is provided with a depending longitudinal guiding rib 53, V-shape in cross-section, slidably mounted in a similar shaped groove formed in the top of the bed 40 and is also provided on its upper side with upstandin transverse,-half dove-tail guideways 54 Fig. 8 to form a broad channel therebetween, in which channel is slidably fitted a transversely movable intermediate plate 55. The upper face of this plate 55 is also provided with guideways 56 paralleling the guideways 54. A grinding tool supporting head 57 is adjustably mounted on the guidewa s 56 for movement to and from the work 7 (Fig. 7).

Drive for tool carriage traverse.

An L-bracket arm 58 (Fig. 5) projects from the right end of the machine and constitutes an out-bearing for one end of a main power shaft 59, to which power is supplied through a pulley 60 belted from any suitable source. The transmission of power from the pulley to the shaft is controlled by means of a friction clutch 61 controlled by the hand lever 62 at the right front of the machine Figs. 2 and 5). A 45 spiral gear 63 (F ig. 6 fixed to the shaft 59 meshes with a similar gear 64 (Fig. 9 fixed to one end of a longitudinally extending shaft 65 journaled in a bracket 66 fixed to the bed frame of the machine below the plate 52 (Fig. 5 A sliding double clutch element 67 (Fig. 9) is keyed to the shaft 65 and is operable between oppositely disposed bevel gear co-acting clutch elements 68 and 69 loose on the shaft.

These bevel gear clutch elements are in mesh continuously with a large vertically disposed bevel gear wheel 70 fixed to the rear end of a short forwardly extending shaft 71 which is journaled centrally in a bracket 72 (Fig. 9 A spur gear 73 keyed to the front end of the shaft 71 meshes with a gear 74 (Fig. 7 mounted on a transverse shaft 75, which is provided at its rear end with a worm 76 meshing with a worm gear 77. This worm gear 77 is fixed to a lead screw 78 (Fig. 5), extending longitu- Drive for turning worm.

A spur gear 82 is fixed to the left end of the lead screw 78 (Fig. 5 and constitutes the driving element of an upwardly and forwardly extending train of gears (Fig. 3*), four of which gears are shown for the particular type of worm illustrated. The gears are accessible from the left end of the machine and the intermediate gears 83 and 84 of this train are adjustably mountedin the rocking frame 85 which is pivoted to a bracket 86 (Fig. 6 and which is fastened in adjusted position by means of the bolt and slot connection 87 (Fig. 3

The driven gear 88 of the train is fixed to a short shaft 89 (Fig. 11 carrying a spur gear 90 within the frame 41. The gear 90 meshes with a gear member 91 loose on a longitudinally extending shaft 92. The

.member 91 includes a bevel gear 93 constitutingthe left end of a differential gear set 94 eve] gear 93 meshes with both of the bevel gears 95, rotatably mounted on the block 96 of the gear set to rotate the same when the right hand member 97 of the set is locked against rotation by the mechanism shown in Figs. 3? to 3' and hereinafter described. The block 96 is pinned to the shaft intermediate its length. A bevel gear 98 is keyed to the inner end of the shaft 92 and meshes with a bevel gear 99 pinned to a transverse shaft 100, the forward end of which projects through the front face of the head stock 41, for a purpose hereinafter described.

A worm 101 is normally clamped to the shaft 100 and meshes with a worm wheel 102 (Fig. 11 keyed to a live center spinwheel.

dle 103 rotatably mounted in bearings 104 and in turn driving the live center 50 demountably fitted therein. The spindle has a face plate 105 fixed thereto from which plate projects a pair of lugs 106 (Fig. 11) carrying centering screws 107" engaging opposite sides of the tail 108 of a dog 109 clamped to the ad'acent end of the work by dog screw 110. y means of this mechanism the work \V is rotated in one direction (indicated by the arrow in Fig. 11') while the lead screw is advancing the tool carriage in if: grinding direction toward the head stoc Mechanism for moving carriage backward.

A rack 111 (Fig. 8) depends from the bed plate 52 and meshes with a lar e gear wheel 112 fixed to a shaft 113 1g. 7) which projects forwardly throu h the front face 0 the bed frames 40 ig. 1*). A toothed ratchet wheel 114 of relatively large diameter is fixed to the front end of the shaft (Fig. 1) in position accessible to the operator. A pair of adjustable arms 115 are pivotally mounted upon the I rear hub of the wheel 114 (Fig. 1) and are designed to extend upwardly therefrom on opposite sides of a vertical line extending through the axis of the wheel 114. As these arms are similar in construction a detailed description of one will sufiice for both. The arm 115 is provided with a block 116 lapping the upper portion of the periphery of the The block is )rovided with a spring pressed latch 11? (Fig. 1 for locking the block in adjustable position on the toothed wheel. The block is also provided with a pair of parallel set screws 118 and 119 threaded through the block in the plane of the wheel and projecting toward said "ertical line through the wheel axis. Preferably the set screws are positioned between the block and a plate 120 (Fig. 1 defining its rear face. A screw bolt 121 extends transversely through the block and plate for fastening the screws in place and this bolt may also constitute means for clamping a shouldered periphery of the wheel 114 between split portions 122 of the block (Fig. 1

The inner screws 118 are designed, as they are moved upward and inward by rotary movement in each direction of the wheel 114 to engage an arm 123 (Fig. 1) the lower end of which is pivoted to the front of the frame 40, and the upper end of which is connected by means of a link 125 to a pivoted arm 124 (Fig. 1*) at the left of the machine. The lower end of the arm 124 is pivoted to a transverse shaft 126 (Fig.5 which shaft turns the longitudinally ex tending shaft 127 through meshed bevel gears 128 and 129. The shaft 127 parallels the lead screw and drives the bevel gear 130 slidably keyed thereto. This gear acts through the gear 131 (Fig. 8*) on the vertically extending shaft 132 to rotate the finger 133 (Fig. 8) which constitutes a lateral projection from one side of a hub 134 pinned to the upper end of this vertical shaft. The revolving finger works in a notch 135 in the side of the lower member of a transversely extending L-shaped bar 136 fixed to the underside of the transversely movable plate 55. This movement of the finger acts in one direction to throw the plate 55 rearwardly a distance sufiicient to permit the tool to clear the work (Fig. 6) on its reverse traverse. The upper portion of the hub 134 is rovided with a sector plate 137 centrally disposed over the finger and constituting a cam for bearing against the side of the upper portion of the L-bar 136.

Mechanism for indexing work.

A hand lever 138 (Fi 1) is pivoted to a transverse shaft 139 a ove the wheel 114 and is dispose in the path of travel of the upper screws 119. A swinging yoke arm 141 (Figs. 7 and 10) depends from the end of the shaft 139 within the frame of the machine.

The lower end of the lever 141 is rounded and straddles a collar 142 loose on a longitudinally extending reversing actuating rod 143 slidably mounted in the inwardly extending arms 144 of bracket 145 (Fig. 9 A pair of spaced apart catch blocks 146 and 147 are pinned to the rod 143 on opposite sides of the collar. A pair of springs 148 and 149 bear respectively on each of the blocks and have their adjacent ends bearing on opposite sides of the collar thereby to form a spring drive between the collar and the rod for movement in either direction. The top face of each block is provided with an outwardly facin shoulder 150 adapted respectively to (Salli the inwardly facing shoulder 151 on the underside of stop latches 152a-nd 153. These latches are pivoted to the bracket arms 144 and extend horizontally toward each other. The latches are designed to be raised into unlatched position by .fingers 154 projecting laterally from opposite sides of the yoke arm 141 and engaging under the free ends of the latches when the voke arm approaches the end of its swing. The rod 143 is connected by means of' a pivoted link 155 to the upper end of an rovided with a lower tail end 140 arm 156 (Fig. 9 fixed to a transverse shaft 7 pinned to the drum with the disk positioned posed trip lever 161, which lever is pivoted intermediate its length to a sliding clutch member 162. The member is keyed to a main indexing shaft 163 which extends longitudinally of the machine beneath the work table and head stock frame and projects through the right end of the machine. The clutch element is in the form of a sleeve provided with a peripheral groove 164 in which are position rollers 165 journaled in opposite ends of a rocking yoke arm 166 loosely pivoted to the shaft 157. A depending arm 167 of the yoke arm is engaged by a spring 168 acting on the clutch element to move the same into unclutched position. The clutch member is provided with beveled clutch teeth 169 on its outer face designed to engage the teeth of a coacting clutch member 170 loose on the shaft 163. A vertically disposed spring 171 connects the right hand end of the trip lever 161 with a horizontally disposed arm 172 of the bell crank lever 158 to hold the trip lever resiliently in bearing engagement with the top of the finger 159. The clutch member 170 includes a sleeve which extends through the right end of the frame 40 and is provided at its outer end with a worm gear 173 meshing with a worm 174 (Fig. 2) carried on a transverse shaft 175 mounted on the right end of the machine. A spiral gear 176 is fixed to the shaft 175 and is driven continuously from .the spiral gear 63. By this construction the indexing shaft 163 is rotated when the carriage has reached the end of its grinding traverse.

The shaft 163 (Fig. 5 has a spur gear 177 fixed thereto adjacent its left end (Fig. 3 which meshes with a spur gear 178 fixed to the outer end of a sleeve 179 journaled in the end of the machine. The gear 178 is of slightly less diameter than the gear 177 so that the gear 177 will not only cause the gear 178 to turn once but will also possess some rotary motion after the indexing mechanism connected thereto has made a complete turn. The inner end of the sleeve is defined by a Hat disk 180 constituting one element of a friction clutch drive. The sleeve constitutes a bearing for the outer end of a secondary indexing stud shaft 181 extending to the outside of the machine. A clutch member 182 for coacting with the disk 180 is fixed to the shaft 181 and comprises a drum 183 pinned to the shaft and a fiat ring 184 loose on the sleeve 179 and therebetween. Leather friction rings 185 are positioned between the faces of the disk and the adjacent faces of the drum and rlng. A short clutch controlling shaft 186 is journaled below and parallels the shaft 181. The inner end of this shaft 186 is provided .with a tripping arm 187 adapted to be lowered from the position shown in Fig. 6

against the action of spring 187 b means of a pin 188 projecting laterally mm the hub of the gear 177. The outer end of the shaft 186 is provided with an arm 189, the outer end of which is defined by a tooth 190 designed to lock in the teeth of the gear 191 and in a notch 191' in the drum 183 (Fig. 3 to lock the shaft 181 against rotation. A bell-crank lever 192 is mounted loosely on the hub of the arm 189. An upwardly extendin arm 193 of this lever constitutes a pawl or engaging a notch 194 in the periphery of the ring 184 to prevent reverse movement of the shaft 181. A spring 195 acts on the other arm 196 of the bellcrank lever to maintain the arm 193 in resilient bearing engagement with the periphery of the rin 184 when in rotation.

The gear 191 Fig. 3 is fixed to the outer end of the shaft 181 and constitutes the driving element of a train of gears the last gear 197 (Fig. 11) of which traln is fixed to a shaft 198 extending into the frame 41. One, or more intermediate gears 199 of the train are adjustably and demountably positioned on a transversely swinging frame 200 (Fig. 3*) designed to mesh different size gears with the relatively fixed gears 191 and 197.

Mechanism for carrying indexing movement through head stock.

The shaft 198 (Fig. 11 has a large gear 201 which meshes with a gear 202 constituting part of the right hand member 97 of the differential set loosely mounted on the shaft 92. This member also includes a bevel gear 203 meshing with the bevel ear 95 by means of which the work may e rotated over an angle depending upon the ratio of the gears in the train, 191, 199 and 197.

Mechanism for stopping indemring move ments.

A sleeve 204 (Figs. 9" and 10) having a projecting flange 205 defining one end thereof is pinned to the shaft 163 in rear of the left end of the tri lever 161. The sleeve carries a disk 206 Fig. 9 mounted thereon and facing the flange. The flange and disk. are resiliently connected by means of a weak spring 207 (Fig. 9 housed within a groove 208 (Fi 9") in the adjacent face of the flange. The disk is provided with a finger 209 projecting from its periphery and designed to be rotated b the shaft 163 to bear resiliently on the le t-hand side of the trip lever for raising the right end clear of the finger 159 to permit spring 149 to act 149 or 148 is doing the driving.

.41 echanism for adjusting grinding tool.

The grinding tool head 57 includes a pair of upstanding laterally sJaced side plates 213 (Fig. 8 the front edges of which are outturned and are alined to constitute a guideway for a vertically movable sliding bracket 214 (Figs. 7 and 7). An extension 215 from the upper portion of the bracket projects rearwardly between the plates 213. A vertically extending feed screw 216 has its lower end fixed to the extension and is threaded through a vhand wheel 217 mounted in a head bracket 218 constituting the top of the head 57. A circular rim 219 pro ects forwardly from the front of the bracket 214 (Fig. 7 and outlines an opening 220 extending therethrough. A spindle carriage 221 for the grindin wheel spindle 222 (Fig. 2 is mounte on said rim for rotary movement about a horizontal axis and has an open back face continuous with the opening 220. The carriage is locked in adjusted position by means of bolts 223 passing through curved slots 224 in the circular base 225 of the carriage and intothe front face of the bracket 214. The upper face of the base 225 is provided with a scale 226 (Fig. 7) designed to move past the index mark 227 so as to indicate the angular rotation from normal of the grinding tool.

Grinding tool drive.

The spindle 222 has a grinding tool, preferably an emer wheel 228 demountably fixed thereto. he wheel is partly housed within and projects from one side of a casing 229 constitutin part of the spindle carriage. The spindle is journaled within the casin fixed against end thrusts and has a pul ey 230 keyed thereto and driven b means of belt 231, from a pulley 232 (Fig. 7:12 positioned at the rear of the machine. his pulley 232 is driven from some suitable power by means of a belt 233 passed about pulley 234 (Fig. 4") fixed to the shaft carrying the pulley 232. The pulleys 232 and 234 (Fig. 3 are journaled in a bracket arm 235 ivoted to a rearward extension from the base of the head 57. The belt 231 is stretched under tension by means of a spring 236 which bears on an adjustable nut 237 carried by a rod 238 and on the arm 235. The rod 238 parallels the run of the belt and has its forward end pivoted to the head 57 (Fig. 4

.llanu'al mechanism for feeding grinding tool.

head 57. A transversely disposed feed screw 247 is threaded through the spiral gear 245 and has one end fixed to the forward portion of the plate 55, (Fig. 8). The rearward movement of the head 57 may be limited by an adjustable stop 248 projecting from the rear of the plate 55 and this plate may be similarly stopped by means of the stop 249 projecting from the plate 52.

Mechanism for finding grinding position.

The hand wheel 239 is provided with a hub 250 (Fig. 8*) bearing against the end of the frame 241 and has a cone flange rim 251 extending from the rear face concentric with the shaft 240. A cone disk 252 is loose upon the huband is designed to clutch the rim in which position it is held'by nut 253 threaded on the hub. A pin 254 projects from the cone disk and is designed to be enga ed by a pin 255 extendin upwardly rom a slide plate 256, adjusta le to bring the pin 255 across the path of the pin 254 in which position slide plate is fastened, by nut and slot connection 257, to the top of the frame 241.

Mechanism for adjusting work.

The worm 101 (Fig. 11) has an extension 258 in the form of a sleeve rejecting forwardly through the front of the frame 41 to which extension is fixed a hand wheel 259 held tight against a shoulder 260 on the sleeve b means of a jam nut 261 threaded to the orward end of the extension. The wheel is provided with a centrally disposed cone flan e rim 262 engaged b a cone disk 263 keyed to the shaft 100. he cone disk is normally held in frictional engagement with the wheel by a jam nut 264 threaded to the outer end of the shaft 100 and bearing on the disk.

Mechanism for manually feeding tool.

tool carriage manually .in its longitudinal traverse.

Adjustment of work in machine.

Operation: In operation, the tail stock is slid along the work table and set approximately for the particular length of worm to be ground and is then clamped in place by means of the bolts 46. The work W is centered between the centers 49 and 50,

utilizing the centering recesses at the ends of the work remainin from the previous machine operation. he adjusting screw 48 is manipulated until the work is held suspended between the centers with the desired tension after which the clamping screw 51 is tightened up to lock the work against longitudinal movement. The work is rotated by hand about its axis until the same is in position so that both of the flange faces of adjacent threads are en aged by the grinding wheel as shown in ig. 6 when the wheel is in its set grinding position. This rotary setting of the work is usually by eye, after which the dog screw 110 is tightened onto the work to clamp the same to the face plate 105. The final adjustment so that the grinding wheel will grind exactly the same amount on both sides of the groove is usually made after the grinding wheel has made one or two runs along the worm, by stopping the machine and micrometrically adjusting the centering screws 107 should it be found that the wheel is grinding more on one face than it does on the opposite face.

By means of the mechanism shown in Fig. 11 an alternative method for making the final adjustment and for indexing the worm by hand is illustrated. The nut 264 may be released slightly, thus freeing the shaft 100 from the worm 101. By manipulating the hand wheel 259, the worm 101 is rotated in either direction independently of the shaft. This rotation of the worm acts through the worm wheel 102 and spindle 103 to the live center 50 and to its dog 109.

When the proper rotary adjustment of the work is attained, the nut' is tightened up against the cone 263 again locking the shaft 100 to worm 101.

By either of these means the worm may be delicately rotated about its axis into any desired position and securely locked in this adjusted position. 1

Setting the gear combinations.

The illustrated embodiment of the invention shows the arrangement 'of the parts when a righthand -quadruple-threaded worm is being ground. Should it be desired to grind a left-hand-quadruple-threaded worm, the emery wheel head is swung around to the proper angle to bring the working faces of the grinding wheel into engagement with the worm teeth and an idler gear is either added or subtracted to the gear train formed of the gears 82 to 88 so as to make the worm rotate in the opposite direction while being ground. Should it be desired to grind a worm having a number of teeth difl'erent from the four tooth worm shown, a proper size gear wheel is substituted for the gear wheels 83, 84, as is usual in change gear combinations.

Adjusting grinding wheel and carriage.

A grinding tool, preferably an emery wheel, particularly designed for the worm to be ground, is mounted on the spindle 222 and fastened in place. This emery wheel is trimmed to have a working face fashioned to be the complement of the flank face of the finished worm teeth and where the one grinding wheel is designed to grind opposite faces simultaneously, as in the illustrated machine, the grinding portion of the wheel is provided with a cross-section conforming to the space between the teeth of the finished worm. The emery wheel is then set in its proper grinding position between the threads. Vertical adjustment of the wheel may be attained by rotating the hand wheel "217. An adjustment about a horizontal axis is attained by rotating the spindle carriage 221, the angular movement from normal of which may be ascertained accurately by means of the scale 226. The grinding wheel may be adjusted longitudinally of the work by rotating the hand wheel 265 in one or the other direction. This rotary motion will act through the feed screw 78 to shift the tool carriage and thus cause the working face of the grinding .wheelto approach or recede from the adjacent face of the thread- By means of this construction the grinding tool may be raised or lowered, may be advancedor receded from the axis of the worm, may be advanced parallel to the axis and may be revolved about a horizontal axis perpendicular to the axis of the worm.

Setting reversing mechanism.

The arms 115 on the reversing ratchet wheel 114 are adjusted so that the action of the mechanism for moving the tool to and from its grinding engagement with the worm will be inaugurated automatically when the toolcarriage has reached the limits of its movement in either longitudinal direction. The screw bolt 121 of one of the blocks 116 is loosened thus permitting the sliding of the block about the periphery of the Wheel. The tool carriage is then run manually or mechanically in one direction (longitudinal) until the grinding tool is at the limit of its desired run. The block to be engaged by the arm 123 at this end of the carriage movement is brought up to 1 tool.

engage the arm. The approximate location of the block for this reversing can be found by placing the latch 117 in the tooth of the wheel which will give the nearest engagement with the arm 123 and the final adjustment is made by rotating the screw 118 into engagement with the arm. The screw 119 is then adjusted to enga e the lever at or preferably slightly in a vance of the engagement to the screw 118 with the lever 123, after which the screw 121 is tightened thus locking the block in position and clamp ing the screws against rotation. The carriage is then ,moved to the other desired limit of its grinding movement and the block and screws of the other reversin arm are adjusted on the wheel as previous described.

Operation for grinding wheel traverse.

Assuming that the different parts are set with the reversing mechanism in the position shown in Fig. 10, with the tool carriage at the beginning of its longitudinal traverse and with the sliding plate 55 in its forward position (Fig. 8) and the grinding tool in its operative position fitting between the worm threads, or, preferably just back of any possible grinding position, the operator starts the machine by throwing the hand lever 62 and by starting the drive for rotating the grinding Motion is transmitted from the pulley 60 to the bevel gear-coacting-clutch member 69, large bevel wheel 70, gears 73, 74, worm 76, worm gear 77, and through the lead screw 78, to the nut 81 attached to the bed plate of the carriage. It will thus be seen that the tool carriage is moved from left to right on its initial grinding traverse.

At the same time the rotation of the lead screw acts through the gear train 8288, through the left end of the differential set 94, through meshed gears 98, 99, through worm 101, spindle 103 to the live center 50 and face plate 105 thereby to rotate the worm W. he ratio of rotary movement of the worm to the advance of the tool carriage may be varied by changing the ratio of gears in the change speed train gear 82--88.

M owing grinding head backward.

As the tool carriage is advancing to the right the ratchet wheel 114 is rotating clockwise due to the rack and gear wheel connection 111 and 112 (Fig. 8 and this motion is continued until the screw 118 carried by the left side of the wheel strikes the arm 123 which acts through the link 125 and arm 124 to rotate the chain of shafts 126, 127 and 132 to revolve the finger 133 thereby moving the grinding tool carriage rearwardly out of grinding engagement with the worm and into the position shown in Figs. 6 and 12 The plate 55 is held to the bed plate 52 by the sector cam plate 137, which engages the foot of the L- bar 136, and at the same time insures an easy throw of the tool carriage.

Operation for disconnecting carriage drive.

At approximately the same time that the screw 118 is set to engage the arm 123, the screw 119 on the advancing block is set to engage the lower end 140 of the lever 138. This movement will cause the lever to swing from the position indicated in Fig. 1O .into the position indicated in Fig. 10 As the yoke arm 141 moves the collar 142 to the right, the right hand spring 149 is compressed between the collar and the locked block 147' at the right. Vhen the spring is fully compressed, finger 154 engages the underside of the latch arm 153 to lift the same into the position shown in Fig. 10, thus permitting the release of the held block 147 and freeing the compressed spring to drive the rod 143 to the right from the position'shown in Fig. 105 The springs react through the link 155, arm 156, shaft 157, yoke arm 212 (Fig. 9) to shift the sliding clutch element 67 from the position shown in Figs. 10* and 9 into the neutral position shown in dotted lines in Fig. 10 This will cause the lead screw which has been advancing the tool carriage to be disconnected from the driving shaft 65, thus preventing the further longitudinal traverse of the grinding tool.

Operation of indexing work. The spring drive of the arm 156 causes the finger 159, which in Fig. 10 is in the v, notch 160 on the underside-of the trip lever 161, to act therethrough on the sliding clutch member 162, and causes the same to move to the right until the clutch elements 169 and 170 are in their driving engagement. Rotary motion is then transmitted from the main drive gear 64 through worm 174 to the shaft 163 to turn the same. This shaft causes its gear 177 to rotate and thus and 202 (Fig. 11) to rotate the right hand member of the differential set which in turn act to rotate the shaft 92 and through mesh gears 98 and 99 to rotate the worm 101.

198. This shaft acts through the gears 201 

